Highway Traffic Speed Prediction in Rainy Environment Based on APSO-GRU

In order to accurately analyse the impact of the rainy environment on the characteristics of highway traffic flow, a short-term traffic flow speed prediction model based on gate recurrent unit (GRU) and adaptive nonlinear inertia weight particle swarm optimization (APSO) was proposed. Firstly, the rainfall and highway traffic flow data were cleaned, and then they are matched according to the spatiotemporal relationship. Secondly, through the method of multivariate analysis of variance, the significance of the impact of potential factors on traffic flow speed was explored. Then, a GRU-based traffic flow speed prediction model in rainy environment is proposed, and the actual road sections under different rainfall scenarios were verified. After that, in view of the problem that the prediction accuracy of the GRU model was low in the continuous rainfall scenario, the APSO algorithm was used to optimize the parameters of the GRU network, and the APSO-GRU prediction model was constructed and verifications under the same road section and rain scene were carried out. The results show that the APSO-GRU model has significantly improved prediction stability than the GRU model and can better extract rainfall features during continuous rainfall, with an average prediction accuracy rate of 96.74%.

Study on Stability of Exit Slope of Chenjiapo Tunnel Under Condition of Long-term Rainfall

The exit slope of Chenjiapo Tunnel is located directly above the exit of Chenjiapo Tunnel on Enshi to Laifeng expressway. During the excavation of the exit of the right line of the tunnel, the left side of the front edge of the slope slips. Under the joint action of excavation and rainfall, a large landslide of 6.27×10 4 m 3 and a huge unstable slope of 8.69×10 5 m 3 are formed. The landslide body and unstable slope body not only cause the tunnel to be shut down, but also directly threaten the operation safety of the later expressway. Therefore, in order to study the stability change process of the exit slope of Chenjiapo tunnel under the condition of long-term rainfall, the finite element calculation of the slope is carried out by GeoStudio software. The results show that under the condition of long-term continuous rainfall, the safety factor of the slope decreases with the increased rainfall time, but the reduction rate gradually slows down, and finally tends to be stable. The safety factor of the slope is reduced from 1.187 in the natural state to 1.015, which indicates that the slope is still in a stable state under the condition of long-term continuous rainfall, but the safety reserve is not high, and it is easy to lose stability and damage due to the influence of external adverse factors. As the rainfall continues, the seepage line inside the slope is rising, and the saturated area of the soil at the toe of the slope is increasing. Until the slope begins to drain outwards, the seepage field inside the slope is basically stable. The maximum horizontal displacement of the slope increases with the increased rainfall time, but the increase rate gradually slows down until it tends to be stable. The maximum horizontal displacement of the slope occurred in the middle surface of the slope at the beginning of the rainfall, and gradually transferred to the toe of the slope within 7 days of the rainfall and continued until the end of the rainfall. At the end of the rainfall, the maximum horizontal displacement of the toe of the slope is 0.128 m, and the toe of the slope will be damaged first. At the beginning of the rainfall, the plastic zone of the slope is only scattered at the slope surface and the slope toe. And then as the rainfall continues, the distribution range of the plastic zone in the slope surface, the slope toe and the slide zone gradually widen, and the slope stability gradually decreases. The maximum horizontal displacement and plastic zone of the slope are concentrated at the toe of the slope, the slope presents obvious traction failure characteristics. According to the results of field survey, there are small-scale gravel soil collapses and shear outlets at the front edge of the slope, and the survey results are consistent with the simulation results. It is suggested to set up perfect drainage engineering in the middle and back of the slope, and set anti slide piles and drainage holes at the toe of the slope to reinforce the slope.

MOISTURE AND ECONOMICS STUDY BY THE EFFECT OF MULCHING AND METHODS OF IRRIGATION ON OKRA (HIBISCUS ESCULENTUS L. MOENCH)

Okra (Hibiscus esculentus L. Moench) or Lady’s finger is one of the important vegetables grown throughout the tropics and subtropics. It is one of the most important vegetable grown commercially almost during the year in India. Irrigation scheduling is considered as a vital component of water management to produce higher irrigation efficiency under any irrigation system, as excessive or sub-optimum irrigation both have detrimental effects on productivity parameters of okra (Aiyelaagbe and Ogbonnaya, 1996). Mulching is effective in reducing evaporation, conserving soil moisture and has been known to modify the hydrothermal regime of soil. The result of method of irrigation is found to be non significant due to continuous rainfall. Hence, there are no differences among the methods of irrigation. Mulching with plastic sheet in okra var. VRO-6 proved the best mulch practice which produced superior growth and yield attributing characters

Proportional Trends of Continuous Rainfall in Indian Summer Monsoon

A comprehensive study on the Indian summer monsoonal rainfall (ISMR) is performed in the light of decadal changes in the continuous rainfall events and the number of rainy days using 68 years (1951–2018) of gridded rain gauge data. Non-parametric Mann–Kendall’s test is applied on total rainfall amount, the number of rainy days, number of continuous rainfall events, and rainfall magnitude to find trends over different climatic zones of India for the two periods, 1951–1984 and 1985–2018. Our results found a decreasing trend for more than 4-days of continuous rainfall events during the recent 34 years (1985–2018) compared to 1951–1984. The rate of increase/decrease in extreme/continuous rainfall events does not follow a similar trend in number of continuous rainfall events and magnitude. Moreover, the rainfall is shifted towards a lesser number of continuous rainfall days with higher magnitudes during 1985–2018. During the crop’s sow season (i.e., the first 45 days from the onset date of Indian monsoon), the total number of rainy days decreased by a half day during the last 34 years. Over the Central and North East regions of India, the number of rainfall days decreased by ~0.1 days/yr and ~0.3 days/yr, respectively, during 1985–2018. Overall, the decreasing trends in continuous rainfall days may escalate water scarcity and lead to lower soil moisture over rain-fed irrigated land. Additionally, an upsurge in heavy rainfall episodes will lead to an unexpected floods. On a daily scale, rainfall correlates with soil moisture and evaporation up to 0.87 over various land cover and land use regions of India. Continuous light-moderate rainfall seems to be a controlling factor for replenishing soil moisture in upper levels. A change in rainfall characteristics may force the monsoon-fed rice cultivation period to adopt changing rainfall patterns.

Unsaturated seepage and stability of double-layer slope under rainfall infiltration

Taking a homogeneous double-layer soil slope as an example, the SEEP/W module and SLOPE/W module in the finite element analysis software GeoStudio were used in this paper. Then, the changes of pore water pressure and stability under different rainfall patterns and soil parameters were studied. Finally, the variation curves of pore water pressure and slope safety factor with rainfall time were obtained. The results show that: Soil parameters a and m are directly proportional to the slope safety factor, while n is inversely proportional to the slope safety factor. Under the condition of continuous rainfall, the decreasing rate of slope safety factor is directly proportional to the rainfall intensity.Under different rainfall patterns, the continuous rainfall in the advanced and normal rainfall patterns will cause the slope stability to decline and then gradually recover, while delayed and averaged rainfall patterns rainfall will cause the slope stability to decline continuously.In addition, there is a lag period in the change of slope safety factor, and the whole lag period lasts about 6 hours. During the lag period, the pore water pressure inside the soil began to decrease, while the slope safety factor continued to decrease. The safety factor starts to recover after the lag period ends.